Lubricant compositions

ABSTRACT

REACTION PRODUCTS OF HIGH MOLECULAR WEIGHT ALKYLPHENOLS, ALDEHYDES AND N,N-DIALKYL, HYDROXLAKYL OR AMINOALKYL-ALKYLENE DIAMINES ARE ASHLESS DISPERSANTS FOR LUBRICATING OILS.

United States Patent ABSTRACT OF THE DISCLOSURE Reaction products of high molecular weight alkylphenols, aldehydes and N,N-dialkyl, hydroxylalkyl or aminoalkyl-alkylene diamines are ashless dispersants for lubricating oils.

5 Claims This application is a division of appliction Ser. No. 523,022, filed Jan. 26, 1966, now US. 3,413,347.

This invention relates to an ashless lubricating oil dispersant. In particularly, this invention relates to the condensation products of an alkylphenol, an aldehyde and a diamine and to improved lubricating oil compositions containing this condensation product.

A large percentage of todays automobiles are used in city stop-and-go driving where the engines do not reach their most efiicient operating temperatures. Large amounts of partial oxidation products are formed and reach the crankcase of the engine by blowing past the piston rings. These partial oxidation products react with oil in the crankcase and lead to the formation of deposits on various operating parts of engines, resulting in sludge and varnish. Other deposits and organic acids result from deterioration of the oil itself. To prevent deposition of these materials on various engine parts, it is necessary to incorporate dispersants in the lubricating oil compositions, thus keeping these polymeric products highly dispersed in a condition unfavorable for deposition on metals.

For the most part the various dispersants which have been used to effectively disperse the precursors of sludges and varnishes are metal organic compounds, particularly those compounds wherein the metal is linked to an organic group through an oxygen atom. These dispersants also neutralize to some extent the organic acids, and thereby help prevent corrosion of the engine parts. How ever, such dispersants have the disadvantage of forming ash deposits in the engine, which deposits lower engine performance by fouling the spark plugs and valves and by contributing to preignition. Therefore, a need exists for a dispersant that effects the removal of sludge and varnish from internal combustion engines, but does not form ash deposits in the engine. The present invention fulfills this need.

It is an object of this invention to supply ashless dispersants. A further object is to supply ashless dispersants of superior dispersant power by condensing an alkylphenol with an aldehyde and a diamine. A still further object is to supply lubricating oil compositions of high dispersancy.

These and other objects are accomplished by providing a dispersant made by (A) condensing an alkylphenol having the formula:

ice

wherein 'R is an alkyl radical having an average molecular weight of from 550 to 1400, with (B) an aldehyde having the formula:

wherein R is hydrogen or an alkyl radical containing from 1 to 6 carbon atoms, and (C) a diamine compound having the formula:

/E4 HzN-Ra-H (III) wherein R is a divalent alkylene radical containing from 1 to 6 carbon atoms, and R and R are selected from the group consisting of alkyl radicals containing 1 to 6 carbon atoms and radicals having the formula:

V) wherein R is a divalent alkylene radical containing from 1 to 6 carbon atoms and X is selected from the group consisting of the hydroxyl radical and the amine radical.

In a preferred embodiment the aldehyde used in the above condensation reaction is formaldehyde. In a still further preferred embodiment the diamine reactant represented by above Formula III is N,N-dimethyl-1,3-propanediamine.

The alkylphenol reactant represented by Formula I is an alkylphenol wherein the alkyl radical has an average molecular weight of from about 550 to 1400. In a more preferred alkylphenol reactant the alkyl radical has an average molecular weight of from about 800 to 1300, and in the most preferred alkylphenols the alkyl radical has an average molecular weight of from about 900 to 1100.

Alkylphenols suitable for use in'the preparation of the present dispersants are readily prepared by adaptation of methods well known in the art. For example, they may be prepared by the acid catalyzed alkylation of phenol with an olefin. In this method, a small amount of an acid catalyst such as sulfuric or phosphoric acid, or preferably a Lewis acid such as BF -etherate, BF -phenate complex or AlC1 HSO is added to the phenol and the olefin then added to the phenol at temperatures ranging from about 0 up to 200 C. A preferred temperature range for this alkylation is from about 25 to 150 C., and the most preferred range is from about 50 to C. The alkylation is readily carried out at atmospheric pressures, but if higher temperatures are employed the alkylation may be carried out at super atmospheric pressures up to about 1000 p.s.i.g.

'Ihe alkylation of phenols produces a mixture of mono-, diand tri-alkylated phenols. Although the preferred reactants are the mono-alkylated phenols represented by Formula I, the alkylation mixture can be used without removing the higher alkylation products. The alkylation mixture formed by alkylating phenol with an olefin using an acid catalyst can be merely water washed to remove the unalkylated phenol and the acid catalyst and then used in the condensation reaction without removing the diand tri-alk'ylated phenol products. Another method of removing the unreacted phenol is to distill it out, preferably using steam distillation or under vacuum, after washing out the alkylation catalyst. The amount of diand tri-al'kylated phenols can be kept at a minimum by restricting the amount of olefin reactant added to the phenol. Good results are obtained when the mole ratio of olefin to phenol is about 0.25 mole of olefin per mole of phenol to 1.0 mole of olefin per mole of phenol. A more preferred ratio is from about 0.33 to 0.9, and a most preferred ratio is from about 0.5 to 0.67 mole of olefin per mole of phenol.

The olefin preactant used to alkylate the phenol is preferably a monoolelfin with an average molecular weight of from about 550 to 1400. The more preferred olefins are those formed from the polymerization of low molecular weight olefins containing from about 2 to carbon atoms, such as ethylene, propylene, butylene, pentane and decene. A most preferred olefin is that made by the polymerization of butene to produce a polybutene mixture with an average molecular weight of from about 900-1100.

The aldhyde reactant represented by Formula II preferably contains from 1 to 7 carbon atoms. Examples are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, hexaldehyde and heptaldehyde. The more preferred aldehyde reactants are the low molecular weight aliphatic aldehydes containing from 1 to about 4 carbon atoms such as formaldehyde, acetaldehyde, butyraldehyde and isobutyraldehyde. The most preferred aldehyde reactant is formaldehyde, which may be used in its monomeric or its polymeric form such as para-formaldehyde.

The diamine reactant is a diamine having Formula III wherein R is a dialkylene radical containing from 1 to 6 carbon atoms and R and R are either alkyl radicals containing 1 to 6 carbon atoms or radicals represented by Formula IV wherein R is a divalent alkylene radical containing from 1 to 6 carbon atoms and X is a hydroxyl or amine radical. The term divalent alkylene radical as used in describing the present invention means a divalent hydrocarbon radical having the empirical formula C H wherein n is an integer of from 1 to 6. The preferred diamine reactants are those in which R is a low molecular weight alkylene radical containing from 1 to about 4 carbon atoms such as the CH C H C H or -C H radicals. The two amine groups of the diamine reactant may be bonded to the same carbon atom, adjacent carbon atoms or to carbon atoms removed from each other by one or more intervening carbon atoms. Some examples of diamine reactants wherein the amine groups are attached to the same carbon atoms of the alkylene radical R are N,N-dialkylmethylenediamine, N,N-dialkanol-l,3-ethanediamine, and N,N-di(aminoalkyl)-2,2propanediamine.

Some examples of diamine reactants in which the amine groups are bonded to adjacent carbon atoms of the R alkylene radical are N,N-dialkyl-1,Z-ethanediamine, N,N-dialkanol-1,2 propanediamine, N,N-di(aminoalkyl)- 2,3-butanediamine, and N,N-dialkyl 2,3 (4-methylpentane) diamine.

Some examples of diamine reactants in which the amine groups are bonded to carbon atoms on the alkylene radical represented by R which are removed from each other by one or more intervening carbon atoms are N,N- dialkyl-l,3-propanediamine, N,N-dialkanol 1,3 butanediamine, N,N di(aminoalkyl)-1,4-butanediamine, and N,N-dialkyl-1,3-hexanediamine.

As previously stated, R and R are alkyl radicals containing 1 to 6 carbon atoms or alkyl radicals containing 1 to 6 carbon atoms which are substituted With the hydroxyl or amine radical. Some examples of hydroxyl substituted radicals are Z-hydroxy-n-propyl, 2-hydroxyethyl, 2-hydroxy-n-hexyl, 3-hydroxy n propyl, 4-hydroxy-3- ethyl-n-butyl, and the like. Some examples of amine substituted R and R radicals are 2-aminoethyl, 2-amino-npropyl, 4-amino-n-butyl, 4-amino-3,3-dimethyl-n-butyl, 6- amino-n-hexyl, and the like. Preferred R and R radicals are unsubstituted alkyl radicals such as methyl, ethyl, npropyl, isopropyl, sec-butyl, n-amyl, n-hexyl, Z-methyl-npentyl, and the like. The most preferred R and R substituents are methyl radicals.

Some specific examples of diamine reactants are:

N,N-dimethyl-1,3-propanediamine; N,N-dibutyl-1,3-propanediamine; N,N-dihexyl-l ,3-propanediamine; N,N-dimethyl- 1 ,2-propanediamine; N,N-dimethyl- 1 l-propanediamine; N,N-dimethyl- 1 ,3-hexanediamine; N,N-dimethyl-1,3-butanediamine; N,N-di(2-hydroxyethyl) -1,3-propanediamine; N,N-di(2-hydroxybutyl) -1,3 -propanediamine; N,N-di 6-hydroxyhexyl) -1, l-hexanediamine; N,N-di(2-aminoethyl)-1,3-propanediamine; N,N-di (2-amino-n-hexyl 1,2-butanediamine; N,N-di (4-amino-3,3-dimethyl-n-butyl) -4-methyl-1,3-

pentanediamine; N- 2-hydroxyethyl -N- (2-aminoethyl) -l,3-

propanediamine.

The condensation products are easily prepared by mixing together the alkylphenol, the aldehyde reactant and the diamine reactant, and heating them to a temperature sufiicient to cause the reaction to occur. The reaction may be carried out without any solvent, but the use of a solvent is usually preferred. Preferred solvents are the water immiscible solvents including water insoluble alcohols (e.g., amylalcohol) and hydrocarbons. The more pre ferred water immiscible solvents are hydrocarbon solvents boiling from 50 to about 200 C. Highly preferred solvents are the aromatic hydrocarbon solvents such as benzene, toluene, xylene, and the like. Of these, the most preferred solvent is toluene. The amount of solvent employed is not critical. Good results are obtained when from one to about 50 percent of the reaction mass is solvent. A more preferred quantity is from 3 to about 25 percent, and a most preferred quantity of solvent is from about 5 to 10 percent.

The ratio of reactants can vary from about l-5 moles of alkylphenol to 1-5 moles of aldehyde reactant to 1-3 moles of diamine reactant. A more preferred reactant ratio is 1.5-2.5 moles of alkylphenol to 2.5-4 moles of aldehyde to 1.5-2.5 moles of diamine reactant. A most preferred ratio of reactants is about 2 moles of alkylphenol to about 3 moles of aldehyde to about 2 moles of diamine reactant.

The condensation reaction will occur by simply warming the reactant mixture to a temperature sufiicient to effect the reaction. The reaction will proceed at temperatures ranging from about 50 to 200 C. A more preferred temperature range is from about to 175 C. When a solvent is employed it is desirable to conduct the reaction at the reflux temperature of the solvent-containing reaction mass. For example, when toluene is used as the solvent, the condensation proceeds at about to C. as the water formed in the reaction is removed. The water formed in the reaction co-distills together with the water immiscible solvent, permitting its removal from the reaction zone. During this water removal portion of the reaction period the water immiscible solvent is returned to the reaction zone after separating water from it.

The time required to complete the reaction depends upon the reactants employed and the reaction temperature used. Under most conditions the reaction is complete in from about one to 8 hours.

The reaction product is a viscous oil and is usually diluted with a neutral oil to aid in handling. A particularly useful mixture is about two-thirds condensation product and one-third neutral oil.

The following examples will serve to illustrate the condensation reaction. All parts are parts by weight unless otherwise indicated.

EXAMPLE 1 To a reaction vessel equipped with a stirrer, condenser and thermometer was added 363 parts of polybutene having an average molecular weight of 1100 and 94 parts of phenol. Over a period of 3 hours, 14.2 parts of a 48 percent BF -etherate complex was added while maintaining the reaction temperature between 50 and 60 C. The reaction mixture was then stirred at 55-60 C. for an additional 4.5 hours and then transferred to a second reaction vessel containing 750 parts of water. The aqueous phase was removed and the organic phase washed 4 times with 250 parts of water at 60 C., removing the aqueous phase after each wash. The organic product was then diluted with about 200 parts of n-hexane and dried with anhydrous sodium sulfate. The product was then filtered and the hexane and other volatiles removed by vacuum distillation until the product remaining was at 75 C. at 0.3 mm. Hg. As a reaction product, there was obtained 368.9 parts of an alkylphenol as a viscous amber-colored oil having an average molecular weight of 810.

In a separate reaction vessel was placed 267 parts of the alkylphenol prepared above, 33.6 parts of N,N-dimethyl-1,3-propanediamine and 330 parts of isopropanol. While stirring, 15.8 parts of 95 percent para-formaldehyde was added. The reaction mixture was then refluxed for 6.5 hours. Following this, the solvent and other volatiles were distilled out to a reaction mass temperature of 115 C. at about mm. Hg. The reaction product was a viscous amber-colored liquid having excellent dispersancy effect in hydrocarbon lubricating oils.

EXAMPLE 2 To a reaction vessel equipped with a stirrer, condenser and thermometer was added 934 parts of a polybutene having an average molecular weight of about 900, 196 parts of phenol and 22 parts of a B'F -ether complex containing 48 percent BF The temperature was raised to 60 C. and maintained there for 3 hours, following which 120 parts of water were added. Steam was then injected into the reaction mass, causing the unalkylated phenol to distill out. The steam distillation was continued until almost all the phenol had been removed. About 870 parts of toluene were then added and the organic phase separated and dried over anhydrous sodium sulfate. The toluene was then removed by vacuum distillation until the alkylated phenol reached a temperature of 145 C. at a pressure of 0.2 mm. Hg. Infrared analysis for hydroxyl content showed that the product had an average molecular weight of 1060.

To a second reaction vessel equipped with stirrer, condenser and thermometer was added 313 parts of the alkyldistilled out during this period were condensed and removed from the reaction mass, resulting in 352 parts of the condensation product in the form of a viscous oil.

EXAMPLE 3 To a reaction vessel equipped as in Example 1 was added 260 parts of isopropyl alcohol, 266 parts (0.33 mole) of the alkylphenol prepared as described in Example 1 and 45 parts (0.33 mole) of N,N-di(2-hydroxyethyl)-1,3-propanediamine. While stirring, 15.8 parts (0.5 mole) of 95 percent para-formaldehyde were added. The reaction mixture was stirred at reflux for 6.5 hours, following which the solvent and volatiles were distilled out to a liquid temperature of 115 C. at 15 mm. Hg, leaving a viscous oil soluble residue.

EXAMPLE 4 To a reaction vessel equipped with stirrer, thermometer and condenser is added 3000 parts of an alkylated phenol with an average molecular weight of 1500. The phenol is primarily monoalkylated, but small amounts of diand some tri-alkylphenols are present. Following this, parts of para-formaldehyde, 204 parts of N,N-dimethyl-1,3- propanediamine and 200 parts of toluene are added. While stirring, the temperature is raised to C. Toluene distills together with some water. The water is removed from the toluene distillate and the toluene returned to the reaction zone. Over a 4 hour period, during which time water is continuously removed, the reaction temperature rises to about C. Following this, the toluene and other volatile material is removed by reducing the pressure in the system to about one mm. Hg, while maintaining the temperature at about C. and allowing the volatiles to distill out. The resultant product is an ashless lubricant dispersant.

EXAMPLE 5 To the reaction vessel of Example 3 is added 2000 parts of a primarily monoalkyl phenol having an average molecular weight of about 800, 150 parts of para-formaldehyde, 324 parts of N,N-di-(Z-hydroxyethyl)-1,3-propanediamine and 200 parts of toluene. While stirring, the reaction temperature is raised to 100 C. over a 0.5 hour period, and then to 140 C. over a 4 hour period. During the time from 100 to 140 C., the water that codistills with the toluene is removed and the toluene returned to the reaction zone. Following this, the volatiles are removed by vacuum distillation to a product temperature of 150 C. at about one mm. Hg. The resultant product is an ashless lubricant dispersant.

EXAMPLE 6' To a reaction vessel as described in Example 2 is added 1.75 mole parts of a primarily monoalkylated phenol with an average molecular weight of about 1200. Following this, there is added 300 parts of toluene, 90 parts of para-formaldehyde and 2.0 mole parts of N,N- di(Z-aminoethyl)-l,3-propanediamine. The temperature is raised to 100 C. over a 0.5 hour period and then slowly to 150 C. during the next 3 hours. Water co-distills with the toluene and is removed and the toluene returned to the reaction zone. Following this, the volatiles are removed by vacuum distillation until the reaction mass is at a temperature of 150 C. at about one mm. Hg. The product is an ashless lubricant dispersant.

The foregoing examples serve only to demonstrate some of the methods of preparing the product and not to limit the invention to the reactants or reactant ratios shown. Any of the previously described reactants may be used in the process in the ratios previously set forth.

The dispersants of this invention are effective in both hydrocarbon and synthetic lubricating oils including lubricating oils used in spark ignition engines and diesel engines. To prepare oil compositions of this invention, from about 0.01 to about 10 weight percent, and preferably from 1 to 5 weight percent, of a dispersant product of this invention is blended with the base oil. Suitable base oils include petroleum derived hydrocarbon mineral oils and synthetic oils such as sebacates, adipates, silicone, halogen containing organic compounds such as the fluorohydrocarbons, etc., polyalkylene glycol lubricants and organic phosphates. The oils may contain other additives including antioxidants such as 4,4'-methylenebis(2,6- di-tert-butylphenol), zinc dithiophosphate, etc., VI improvers, such as the polymethacrylates, corrosion inhibitors such as the calcium sulfonates, antifoam agents, and the like.

7 The following examples illustrate some of the improved lubricant compositions of this invention.

EXAMPLE 7 Lubricants are prepared by blending a solvent refined hydrocarbon lubricating oil having a viscosity index of 95 and an SAE viscosity of 10 with 0.5 weight percent of 4,4 methylenebis (2,6-di-tert-butylphenol), 0.4 weight percent dialkyl-hydrogen phosphite, 0.1 weight percent of the N-octylamine salt of 1-(octyl)-5-oxo-3-pyrrolidinecarboxylate and adding the following concentration of the indicated dispersant.

Concentration wt.

Dispersant: Examplepercent 3 0.01

EXAMPLE 8 Synthetic lubricating oils are prepared as in Example 7 by blending the following oils with 3.0 weight percent of the product from Example 2.

(A) A dioctyl sebacate having a viscosity at 210 F. of 36.7 SUS, a viscosity index of 159 and a molecular weight of 426.7.

(B) A di(sec-amyl) sebacate having a viscosity at 210 F. of 33.8 SUS, a viscosity index of 133 and a molecular weight of 342.5.

(C) A di-(Z-ethylhexyl) sebacate having a viscosity at 210 F. of 37.3 SUS, a viscosity index of 152 and a molecular weight of 426.7.

(D) A di-(Z-ethylhexyl) adipate having a viscosity at 210 F. of 34.2 SUS, a viscosity index of 121 and a molecular weight of 370.6.

(E) A diisooctyl azelate having a kinematic viscosity of 3.34 centistokes at -65 F., an ASTM slope from 40 F. to 210 F. of 0.693, a pour point of -85 F, a flash point of 425 F. and a specific gravity at 25 C. of 0.9123.

(F) A diisooctyl adipate having a viscosity at 210 F. of 35.4 SUS, a viscosity at 100 F. of 57.3 SUS, a viscosity of 3.980 SUS at -40 F. and a viscosity index of 143.

The reaction products described in this invention are excellent dispersants for lubricating oil. Tests were carried out which demonstrate this property.

Sludge dispersancy test In this test, a neutral oil containing the dispersant is first subjected to high temperature oxidation conditions in a modified Polyveriform Test, as follows. An oil sample is prepared containing 0.08 percent zinc as a zinc dithiophosphate, 0.1 percent lead bromide and percent of the test dispersant. A copper-lead bearing is placed in this test oil and the oil is subjected to a temperature of 300 F. for a period of 48 hours, during which period 48 liters per hour of air are passed through the oil sample. This treatment measures the ability of the test additive to endure under typical engine operating conditions. Following this, a second test blend is prepared using 10 grams of the oil already subjected to the above Polyveriform Test, 83 grams of new oil, 7 grams of a typical sludge material and 2 grams of water. In this blend, the concentration of the test dispersant carried over from Polyveriform is reduced to 0.5 percent. This material is emulsified in a blender for 20 minutes and then centrifuged for 2.5 hours. Following this, the percent light transmittance of the oil is measured. The better the dispersant, the more of the sludge that will remain suspended following the centrifuging, and hence the lower the percent light transmittance that will be measured. The light transmittance of the test oil is compared to the transmittance of the base oil without sludge. This shows the degree of dispersant effectiveness. When this test was carried out on a reaction product like the one prepared in Example 2, the following results were obtained.

Percent light transmittance Before 64 After 1 As the above test shows, the dispersant of the present invention retained the sludge in a dispersed form even after 2.5 hours of centrifuging to such a degree that only about 1.6 percent as much light transmitted through it compared to the light transmitted through the oil without dispersed sludge.

Engine evaluation This test was a modified L43 low temperature sludge test. The test measures the ability of an oil to control sludge deposits under lower temperature engine operating conditions. The engine was a single cylinder OLR engine equipped with a new piston, new piston rings, new polished push rods, and new copper-lead bearings. After one hour break-in, the engine was run under the following test conditions.

Speed 1800 r.p.m.

Load Near full throttle. A/F ratio 15.0.

Intake manifold mixture temp. 175 F.

Water in temp. F.

Water out temp F.

Oil gallery temp F. (approx). Blowby 20 c.f.h.

Intake air humidity 80 grains H O/ lb. air.

Periodic inspections of five critical engine parts for degree of engine deposits are made at 20 hour intervals. Each test is continued until the overall sludge rating of the critical parts is 9.0 on a scale in which 10 is perfectly clear and 0 is the condition at which the critical parts are completely covered with sludge to a depth of about onequarter inch. The oil used in the test is a typical 10W30 solvent refined commercial base oil containing 5.5 volume percent of a commercial polymethacrylate VI improver and 0.08 percent zinc as a zinc dithiophosphate. The following table shows the hours to a 9 sludge rating in the engine test at two different concentrations of the reaction product prepared in *Example 2.

Dispersant conc., percent: hrs. to 9.0 sludge rating The above table shows the high dispersant effect of the reaction products of the present invention in a typical commercial base oil.

I claim:

1. A lubricating oil composition comprising, as a major portion, a lubricating oil and, as a minor portion, a dispersing quantity of an ashless dispersant, said dispersant being the reaction product of:

(A) from 1 to 5 moles of an alkylphenol having the formula:

wherein R is an alkyl radical having an average molecular weight of from 550 to 1400, with (B) from 1 to moles of an aldehyde having the formula:

wherein R is selected from the group consisting of hydrogen and alkyl radicals containing from 1 to 6 carbon atoms, and (C) from 1 to 3 moles of an alkanol diamine compound having the formula:

3. The composition of claim 2 wherein said aldehyde is formaldehyde and said diamineis N,N-di(2-hydroxyethyl) l ,3 -propanediamine.

4. The composition of claim 3 wherein R is an alkyl radical having an average molecular weight of from 900-1100.

5. The composition of claim 4 wherein said dispersant is the reaction product formed by reacting about 2 mole parts of said alkylphenol with about 3 mole parts of said formaldehyde and about 2 mole parts of said N,N-di(2- hydroxyethyl)-1,3-propanediamine..

References Cited UNITED STATES PATENTS 2,459,l l2 1/ 1949 Oberright 252-5l.5

2,962,442 1 1/ 1960 Andress 252-515 3,368,972 2/ 1963 Otto 252'5 1.5 X

FOREIGN PATENTS 637,867 3/ 1962 Canada 252-5 15 PATRICK P. GARVI'N, Primary Examiner W. J. SHINE, Assistant Examiner 

